US underground natural gas storage capacity edges higher in 2025

Underground working natural gas storage capacity in the Lower 48 states increased modestly in 2025, with most additions concentrated in the South Central and Mountain regions, according to the US Energy Information Administration (EIA).

Natural gas storage plays a key role in balancing seasonal demand fluctuations, allowing supplies to be injected during periods of lower consumption and withdrawn during periods of peak demand. EIA calculates natural gas storage capacity in two ways: demonstrated peak capacity and working gas design capacity. Both increased in 2025.

EIA data show demonstrated peak storage capacity rose by 6 bcf, or 0.1%, from the previous year, marking the third consecutive annual increase. Demonstrated peak capacity is the sum of the largest volume of working gas stored in each storage field during the previous five-year period, regardless of when the peaks occurred.

The South Central and Mountain regions posted the largest gains, with demonstrated peak capacity increasing by 16 bcf and 18 bcf, respectively. Capacity declined in other regions, falling 15 bcf in the East, 8 bcf in the Pacific, and 5 bcf in the Midwest.

Working gas design capacity, sometimes referred to as nameplate capacity, is based on the physical characteristics of the reservoir, installed equipment, and operating procedures on the site, which federal or state regulators usually must certify.  As of November, Lower 48 design capacity totaled 4,683 bcf, up 26 bcf from a year earlier.

The South Central region accounted for most of the increase, adding 21 bcf of design capacity, while the Mountain region added 6 bcf. Design capacity in the East declined by 2 bcf, primarily because of base gas adjustments. Capacity in the Midwest and Pacific regions was unchanged from the previous year.